text: Several technologies are currently available for remediating PFASs in liquids. These technologies can be applied to drinking water supplies, groundwater, industrial wastewater, surface water, and other applications such as landfill leachate. Influent concentrations of PFASs can vary by orders of magnitude for specific media or applications. These influent values, along with other general water quality parameters (for example, pH) can influence the performance and operating costs of the treatment technologies. The technologies are:
  * Foam fractionation
  * Sorption
  * Granular activated carbon
  * Biochar
  * Ion exchange
  * Precipitation/flocculation/coagulation
  * Redox manipulation (chemical oxidation and reduction technologies)
  * Membrane filtration
  * Reverse osmosis
  * Nanofiltration
  * Supercritical water oxidation
  * Low Energy Electrochemical Oxidation (EOx)
  Private and public sector applications of one or more of these methodologies above are being applied to remediation sites throughout the United States and other international locations. Most solutions involve on-site treatment systems, while others are leveraging off-site infrastructure and facilities, such as a centralized waste treatment facility, to treat and dispose of the PFAS pool of compounds.
  The US based Interstate Technology and Regulatory Council (ITRC) has undertaken extensive evaluation of ex situ and in situ treatment technologies for PFAS impacted liquid matrices. These technologies are divided into field implemented technologies, limited application technologies and developing technologies and typically fit into one of three technology types:
  *  Separation,
  *  Concentration, and
  *  Destruction
  The type of PFAS remediation technology selected is often a reflection of the PFAS contamination levels and the PFAS signature (i.e. the combination of short and long chain PFAS substances present) in conjunction with the site specific water chemistry and cross contaminants present in the liquid stream. More complex waters such as landfill leachates and WWTP waters require more robust treatment solutions which are less vulnerable to blockage.
  Stripping and Enrichment
  Foam Fractionation utilises the air/water interface of a rising air bubble to collect and harvest PFAS molecules. The hydrophobic tail of many long chain criteria PFAS compounds adhere to this interface and rise to the water surface with the air bubble where they present as a foam for harvesting and further concentration. The foam fractionation technique is a derivation of traditional absorptive bubble separation techniques used by industries for decades to extract amphiphilic contaminants. The absence of a solid absorptive surface reduces consumables and waste byproducts and produces a liquid hyper-concentrate which can be fed into one of the various PFAS destruction technologies. Across various full scale trials and field applications, this technique provides a simplistic and low operational cost alternative for complex PFAS impacted waters.
  Destruction
  Most recently, a 2022 study published in the Journal of Environmental Engineering found that a heat-and pressure-based technique known as supercritical water oxidation destroyed 99% of the PFASs present in a water sample. During this process, oxidizing substances are added to PFAS-contaminated water and then the liquid is heated above its critical temperature of 374 degrees Celsius at a pressure of more than 220 bars. The water becomes supercritical, and, in this state, water-repellent substances such as PFASs dissolve much more readily.